Pharmaceutical hydroxamic acid compositions and uses thereof

ABSTRACT

New and useful phenylalkylcarbohydroxamic acids are disclosed of the formula ##STR1## wherein: (a) R is selected from the group consisting of alkoxy of one to six carbon atoms, alkenyloxy of two to six carbon atoms, alkyl of one to six carbon atoms, and benzyloxy; 
     (b) R 1  and R 2  are each selected from the group consisting of hydrogen, alkoxy of one to six carbon atoms, alkenyloxy of two to six carbon atoms, alkyl from one to six carbon atoms, and benzyloxy; 
     (c) R 3  and R 4  are selected from the group consisting of hydrogen or alkyl of one to six carbon atoms; 
     (d) R 5  is hydrogen or R 5  together with R 3  or R 4  represent methylene; and 
     (e) n signifies the number 0 to 1, 
     and non-toxic salts thereof, which novel compounds exert a pronounced inhibition of blood platelet aggregation and accelerate the disaggregation of platelet aggregates already formed.

This is a division of application Ser. No. 859,142 filed Dec. 9, 1977.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention disclosed is referring to the preparation of novelphenylalkylcarbohydroxamic acids substituted in the phenyl nucleus andto the use thereof in a pharmaceutical formulation; and relates to thefield of hydroxamic acids employed for the inhibition of blood plateletaggregation.

2. Description of the Prior Art

Certain substituted phenylalkylcarbohydroxamic acids are known to thoseskilled in the art. Biologically active phenylmethylcarbohydroxamicacids possessing at least a substituent in the para-position ("p"position) are known from Belgian Pat. Nos. 648,892 and 661,226.Substituted phenylvinylcarbohydroxamic acids have furthermore beendescribed in the Belgian Pat. No. 701,983. From the numerouspublications with respect to these known hydroxamic acid derivativeswhich have appeared in the literature, such as 211 NATURE 752 (1966), 18ARZNEIMITTELFORSCHUNG 1404 (1968), and J. MED. CHEM. 13, 211 (1970), itis obvious that a predominant characteristic of these compounds is apronounced anti-inflammatory activity, with possible side-effects in theCNS field, such as a sedative action. Studies of the structure-activityrelationships have inter alia shown that the anti-inflammatory activityis restricted to the hydroxamic acids derived from substitutedphenylacetic acid derivatives and to a less extent from cinnamic acidderivatives. It is emphatically stated in 13 J. MED. CHEM. 211 (1970)that hydroxamic acids derived from substituted phenylpropionic acidderivatives no longer show any anti-inflammatory activity. Hence, a needarose in the art to (1) abolish the anti-inflammatory activity of suchhydroxamic substituted acids; (2) not to retain sedative properties; (3)not to intensify CNS activity; while (4) trying to utilize any bloodplatelet aggregative inhibition properties.

Also it may be noted in 18 ARZNEIMITTELFORSCHUNG 1404 (1968) thatremoval or blockage of the hydroxylamine function (of the hydroxamicacid concerned) also causes to a great extent the anti-inflammatoryactivity to disappear. This statement is more or less confirmed by (1)the U.S. Pat. No. 3,190,800, which teaches that ethers of a large groupof hydroxamic acids (including phenylalkylcarbohydroxamic acids) aredepressives, and by (2) the French Pat. No. 1,332,352, which teachesthat lower alkyl ethers of the hydroxamic acid derived from3,4,5-tri-alkoxy-substituted cinnamic acid are sedatives.

On the basis of the above information, a conclusion that conversion toan ether group of the known hydroxamic acids (derived from substitutedphenylacetic acid and substituted cinnamic acid) abolishes theanti-inflammatory activity, but considerably intensifies CNS activity,would be justified to one skilled in the art.

Additional patents of interest are U.S. Pat. Nos. 3,890,377 and3,972,934 to Winston S. Marshall. Both U.S. Pat. Nos. 3,972,934 and3,890,377 disclose selected 3-phenoxy-phenylalkyl amines (and theamides, alcohols, tetrazoles and carbamates related thereto) useful asanti-inflammatory agents with favourable analgesic and anti-pyretic sideeffects. Buu Hoi in U.S. Pat. No. 3,479,396 teaches the manufacture of agroup of substituted arylaceto hydroxamic acids prepared by reactinghydroxylamine and alkyl acetate, in which the meta-position isoptionally substituted. This U.S. patent corresponds to the two Belgiumpatents cited above. Finally, Nordman in U.S. Pat. No. 3,383,407 teachesthe manufacture of 3,4,5-trimethoxybenzohydroxamic acids having sedativeproperties.

Surprisingly, it has now been found that hydroxamic acids derived fromat least meta-substituted phenylpropionic acid and phenylbutyric acidderivatives exert a pronounced inhibition of blood platelet aggregation,while they also accelerate considerably the disaggregation of plateletaggregates already formed.

SUMMARY OF THE INVENTION

New and useful compounds represented by the general formula: ##STR2##and non-toxic salts thereof, wherein (a) R is selected from the groupconsisting of alkoxy of one to six carbons, alkenyloxy of two to sixcarbons, alkyl of one to six carbons and benzyloxy;

(b) R₁ and R₂ are each selected from the group consisting of hydrogen,alkoxy, alkenyloxy, benzyloxy and alkyl of one to six carbons;

(c) R₃ and R₄ are each selected from the group consisting of hydrogenand alkyl of one to six carbon atoms;

(d) R₅ is hydrogen or R₅ together with R₃ or R₄ represent methylene, and

(e) n signifies the number 0 or 1,

may be used most appropriately for the control or prevention of thrombusformation.

The compounds according to formula I herein referred to possess nonoteworthy anti-inflammatory activity, which is in agreement with theconclusions of the article in 13, J. MED. CHEM. 211 (1970) where it isstated that for the possession of good anti-inflammatory activity it isessential that the carbohydroxamic acid function is only separated fromthe benzene ring by one carbon atom.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The hydroxamic acids according to the present invention are prepared ina way which is generally known for the preparation of hydroxamic acids.

The most usual method for the preparation of the hydroxamic acidsconcerned consists of the reaction of a carboxylic acid with the generalformula: ##STR3## or an ester, acid halide or anhydride thereof, whereR, R₁, R₂, R₃, R₄, R₅ and n have the meanings assigned above, withhydroxylamine. See Example I incorporated herein by reference.

The condensation of the free acid according to formula II withhydroxylamine is preferably performed in the presence of a dehydratingagent, for example a carbodi-imide such as dicyclohexylcarbodi-imide.

In the condensation of an ester according to formula II withhydroxylamine use is preferably made of a lower aliphatic ester of fromone to six carbon atoms such as the methyl, ethyl, isopropyl, propyl,butyl, pentyl, or hexyl ester. (See Example I and II).

The starting compounds according to the general formula II and theesters, acid halides and anhydrides derived from these compounds areknown. They may be prepared in obvious ways known to those skilled inthe art.

For example, acids of formula II where n is 0, and R₃ and R₄ representhydrogen may be prepared by catalytic reduction of the correspondingcinnamic acid derivative. Compounds according to formula II in which nis 0 or 1, and at least one of R₃ and R₄ represents hydrogen, may beprepared by a Wittig reaction (at from about -20° C. to about 80° C. andat a pressure of about 0.5 atm to about 1.5 atm) of the appropriateWittig reagent with a benzaldehyde or phenylalkylketone (derived forexample from acetophenone), substituted in the phenyl nucleus, followedby catalytic reduction of the unsaturated compound obtained at atemperature of from about -20° C. to about 120° C. and a pressure fromabout 1 atm to about 10 atm. Compounds according to formula II in whichboth R₃ and R₄ represent an alkyl group may for example be prepared by(a) halogenating a 1,1-dialkylbenzyl alcohol substituted in the phenylnucleus (for example, a 2-phenylisopropyl alcohol substituted in thephenyl nucleus), (b) converting the halide thus obtained into thecorresponding nitrile with the aid of potassium or sodium cyanide, (c)subsequently hydrolysing the nitrile to the corresponding carboxylicacid (after which the carboxylic acid is reduced to the correspondingalcohol with, for example, lithium aluminium hydride and the entireprocedure is repeated again once or twice).

Compounds according to formula II, in which R₃ and R₅ together representa methylene group, may for example be prepared by reacting a styrenederivative (substituted in the phenyl nucleus) with diazo-acetic esteror by reacting a cinnamic-ester derivative or a β,γ-unsaturated butyricacid ester derivative with diazo-methane.

By an alkyl group in the definition of R, R₂, R₃ and R₄ is meant abranched or straight-chain alkyl group with from one to six carbonatoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert.butyl, amyl, iso-amyl, tert. amyl, hexyl and isohexyl.

The alkyl part of the alkoxy group as meant in the definition of R, R₁and R₂ has the same significance.

By an alkenyloxy group in the definition of R, R₁ and R₂ is meant anunsaturated hydrocarbon residue with two to six carbon atoms, such asvinyl, allyl, β-allyl, iso-allyl, 1-butenyl, 2-butenyl, 3-butenyl,iso-butenyl, 2-methylallyl, 1-pentenyl and 3,3-dimethylallyl groups.

The compounds according to the invention may be administered by theoral, rectal or parenteral routes in pharmaceutically effective amounts,preferably in a daily dosage of from about 0.01 to about 100 mg per kgbody weight.

When mixed with suitable excipients, the compounds according to theinvention may be compressed to give solid formulations such as pills,dragees, tablets or suppositories. Examples of suitable excipients arelactose, starch, magnesium stearate, etc. Optionally mixed with theusual pharmaceutical excipients, they may also be processed to givecapsules. With the aid of suitable liquids, the compounds mayfurthermore be used as injection preparations in the form of sterilesolutions, emulsions or suspensions.

Compounds according to the invention which are preferably used are thosecompounds according to the general formula I, in which

n signifies the number zero, and

R represents an alkoxy, preferably a methoxy group.

From this group of preferred compounds those, in which

(a) R₃, R₄ and R₅ are hydrogen, or

(b) R₃ is methyl and R₄ and R₅ are hydrogen, or

(c) R₃ +R₅ is methylene and R₄ is hydrogen, are particularly valuable.

Among these preferred compounds, those compounds which contain onefurther substituent in the para-position, in particular an alkoxy,alkenyloxy or benzyloxy group, are particularly preferred. Aparticularly valuable compound is the compound3-(3,4-dimethoxyphenyl)propionohydroxamic acid.

The compounds according to the general formula I may be converted intopharmaceutically acceptable non-toxic salts. These salts which are alsonumbered among the compounds of the invention are prepared by reactingthe acid of formula I with a suitable alkaline substance, such as analkalimetalhydroxide. The sodium salts of the acids of formula I arepreferred.

EXAMPLE I

Preparation of 3-(3,4-dimethoxyphenyl)propiono-hydroxamic acid. Asolution of 8.44 g powdered 88% KOH (132.6 mmol) by weight in 25 mlmethanol is added to a solution previously obtained by dissolving 6.15 ghydroxylamine HCl (88.4 mmol) in 40 ml methanol at 50° C. After standingfor 3 minutes in an ice-bath, the resultant KCl is filtered off and thefiltrate is added to 10.0 g methyl 3-(3,4-dimethoxyphenyl) propionate.After stirring for 20 hours at room temperature, solvent is removed byevaporation without increasing the temperature and the residue isneutralized with 6 N HCl. Extraction with ethyl acetate, evaporation todryness and crystallization of the residue from chloroform-hexane gives7.70 g 3-(3,4-dimethoxyphenyl)propionohydroxamic acid. Repeatedcrystallization from chloroform-hexane gives a substance of analyticalpurity with a melting point of 105°-106° C.; Rf in toluene-ethanol(8:2)=0.45 (on SiO₂). Generally, this condensation reaction may takeplace at a temperature of from about -20° C. to about 100° C. and at apressure of from about 0.5 atm to about 5 atm.

EXAMPLE II Preparation of 3-(3-methoxy-4-allyloxyphenyl)propionohydroxamic acid

(a) 13.1 g methyl 3-(3-methoxy-4-hydroxyphenyl) propionate (62.4 mmol)is dissolved in 150 ml dry N,N-dimethylformamide (DMF). After additionof 4.0 g 88% KOH (62.7 mmol) to this solution, the whole is stirred for30 minutes, after which 7.55 g allyl bromide (62.4 mmol) in 120 ml dryDMF is added dropwise over a 30-minute period. After stirring for 11/2hours at room temperature, the reaction mixture is poured out into 1700ml saturated NaCl solution. Extraction with ethyl acetate, evaporationto dryness and chromatography on 150 g silica gel with toluene-ethylacetate (95:5) as eluent gives 12.4 g methyl3-(3-methoxy-4-allyloxyphenyl)propionate as an oil. Rf intoluene:ethyl-acetate (85.15)=0.5 on SiO₂.

(b) 12.4 g methyl 3-(3-methoxy-4-allyloxyphenyl) propionate is treatedwith hydroxylamine at conditions corresponding to that described inExample I. The yield of 3-(3-methoxy-4-allyloxyphenyl)propionohydroxamic acid is 11.5 g. Crystallization from amethanol-toluene mixture gives an analytically pure sample of meltingpoint 94°-95° C.

EXAMPLE III

The following compounds are prepared in a way corresponding to thatdescribed in Example I:

3-(3,5-dimethoxyphenyl)propionohydroxamic acid; melting-point 92°-94°C.;

3-(3-methoxyphenyl)propionohydroxamic acid; melting-point 76°-77° C.;

3-(3,4-dimethylphenyl)propionohydroxamic acid; melting-point 95°-98° C.;

3-(3,4,5-trimethoxyphenyl)propionohydroxamic acid; melting-point122°-123° C.;

3-(3-methoxy-4-butoxyphenyl)propionohydroxamic acid; melting-point82°-83° C.;

2,3-methylene-3-(3,4-dimethoxyphenyl)propionohydroxamic acid; meltingpoint 138° C.;

3-(3-methoxy-4-benzyloxyphenyl)propionohydroxamic acid; melting point123°-124° C.;

3-(3-benzyloxy-4-methoxyphenyl)propionohydroxamic acid; Rf in methylenechloride:methanol (85:15)=0.58 on SiO₂ ;

4-(3,4-dimethoxyphenyl)butyrohydroxamic acid; melting point 121°-123°C.;

3-(3,4-dimethoxyphenyl)-3-methyl-propionohydroxamic acid; melting point125°-127° C.

EXAMPLE IV

In order to illustrate that the inhibition of platelet aggregation iscoupled to the compounds of formula I, test results of a number ofrelated hydroxamic acids in the so-called "in-vivo screen filtration"test are given in this Example. In this test the effects of thecompounds to be tested on aggregation of platelets induced in-vivo byadenosine-5'-diphosphate (ADP) are determined. The circulation of bloodthrough the aorta of normal rats, (which have already been treated for 5days with the substance being tested (or placebo)), is diverted to theoutside of the body through a plastic tube. The plastic tube is attachedto a micro-filter system (20 μ) containing heparin. The blood pressurein front of and behind this filter can be recorded at any desired time.By injecting an ADP solution immediately before the filter, plateletaggregation is induced at that point. Aggregates of platelets thenpartially block the filter system, causing a change in pressure acrossthe filter. Two variables are measured: (a) the change in pressureacross the filter (hereinafter aggregation index) and (b) the timenecessary for the original pressure gradient to be restored (hereinafternormalisation time).

The changes in aggregation index and normalization time are expressed aspercentages of the values found for the rats treated with placebo. Thecompounds 1 to 7 inclusive are hydroxamic acids claimed and areaccording to the invention.

    __________________________________________________________________________     ##STR4##                     Screen Filtration Test  % change in                                          Aggre-Normalisa-                                 No.                                                                                  A       R   R.sub.1                                                                             R.sub.2                                                                           Dosage (oral)                                                                         gation index                                                                         tion time                         __________________________________________________________________________    1. CH.sub.2CH.sub.2                                                                          OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    -23    -24                               2. CH.sub.2CH.sub.2                                                                          OCH.sub.3                                                                         H     OCH.sub.3                                                                         5 × 50 mg/kg                                                                    -21    -15                               3. CH.sub.2CH.sub.2                                                                          OCH.sub.3                                                                         H     H   5 × 50 mg/kg                                                                    -6     -28                                   ##STR5##   OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    -10    -42                               5. CH.sub.2CH.sub.2CH.sub.2                                                                  OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    -8     -19                                   ##STR6##   OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    -22    -37                               7. CH.sub.2CH.sub.2                                                                          OCH.sub.3                                                                         OCH.sub.2 C.sub.6 H.sub.5                                                           H   5 × 50 mg/kg                                                                    -24    -28                               8. CH.sub.2CH.sub.2                                                                          H   OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    -1     +4                                9. CH.sub.2CH.sub.2                                                                          OCH.sub.3                                                                         OH    H   5 × 50 mg/kg                                                                     +10   -3                                10.                                                                              CHCH        OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 100 mg/kg                                                                   -2      0                                   CH.sub.2    OCH.sub.3                                                                         OCH.sub.3                                                                           H   5 × 50 mg/kg                                                                    +3     -1                                __________________________________________________________________________

We claim:
 1. A pharmaceutical composition having inhibitive anddisaggregative properties towards blood platelet aggregation,comprising:(A) a therapeutically effective amount to inhibit anddisaggregate blood platelet aggregation of a compound of the formula:##STR7## or a pharmaceutically acceptable non-toxic salt thereof,wherein: (a) R is selected from the group consisting of alkoxy of one tosix carbon atoms, alkenyloxy of two to six carbons and alkyl of one tosix carbon atoms;(b) R₁ and R₂ are each selected from the groupconsisting of hydrogen, alkoxy of one to six carbon atoms, alkenyloxy oftwo to six carbon atoms, alkyl from one to six carbon atoms, andbenzyloxy; (c) R₃ and R₄ are selected from the group consisting ofhydrogen and alkyl of one to six carbon atoms; (d) R₅ is hydrogen ortogether with R₃ and R₄ methylene, and (e) n signifies the number 0 or1; and (B) a pharmaceutically acceptable carrier.
 2. A method forinhibiting and disaggregating blood platelets in humans, which comprisesadministering to a human a pharmaceutical composition comprising:(A) anamount effective to inhibit and disaggregate blood platelets in saidhuman of a compound of the formula: ##STR8## or a pharmaceuticallyacceptable non-toxic salt thereof, wherein: (a) R is selected from thegroup consisting of alkoxy of one to six carbon atoms, alkenyloxy of twoto six carbon atoms and alkyl of one to six carbon atoms;(b) R₁ and R₂are each selected from the group consisting of hydrogen, alkoxy of oneto six carbon atoms, alkenyloxy of two to six carbon atoms, alkyl fromone to six carbon atoms, and benzyloxy; (c) R₃ and R₄ are selected fromthe group consisting of hydrogen and alkyl of one to six carbon atoms;(d) R₅ is hydrogen or together with R₃ and R₄ methylene, and (e) nsignifies the number 0 or 1; and (B) a pharmaceutically acceptablecarrier.
 3. The method of claim 2 wherein the compound is administeredin a range effective amount is from about 0.01 to about 100 mg per kgbody weight.